I. Field of the Invention
This invention concerns an automatically adjusting, tree contour tracking, force-balanced shaker brush harvester apparatus for removing fruit from a tree, bush or plant, and methods of harvesting the fruit, controlling the position of the shaker heads and mounting the shaker brushes in the harvester. This invention also includes a mechanism for an automatic control system for the directional control of the steerable wheels of the harvester.
The particular harvester of this invention is a type that straddles a row of crop, for instance, a row of olive trees in an orchard. It is know as an “over-the-row” harvester. It has an elevated frame supported on four wheels and enough width between the wheels to accommodate the orchard trees. For an orchard harvester the supporting frame may be more than eight feet off the ground to allow the harvester to straddle a tree that is wide and tall. The harvester includes substantially vertical shaker brushes having rod or tines that are positioned into the branches of the tree to induce a vibration in the tree. This causes the fruit to be shaken off the tree.
The vibration is generated by a force-balanced drive for each shaker head.
In a particular embodiment of this invention, the automatically adjusting shaker, harvester or the like has a series of leaf springs cantilevered from a central pivot to act as tree contour sensing feelers. The feelers are mounted to a support collar and clamped to a shaft. Their position is adjustable horizontally, vertically, and in length—by replacing a first leaf spring of one length with a second leaf spring of a different length—, to profile the general tree, bush or plant shape, e.g. a conical shaped tree profile. The feelers are adjustable depending on the tree, bush or plant shape profile. For example, the tree profile may comprise more of a vertical hedgerow shape without gaps between the trees. In this situation the length of the feelers may be adjusted. That is, at least some of the feelers are adjusted to be shorter than they would be when set up for picking from a conical shaped tree.
An alternative embodiment of this invention uses a linkage connected to a linear potentiometer to sense tree position. The linkage can include any of several arrangements where sensors or sensor bars and frames move laterally to impart linear motion input to the linear potentiometer.
Another embodiment of this invention uses a rotary potentiometer as a control element of a tree sensing and reaction system.
Another embodiment uses a rotary hydraulic valve in communication with a linear motor—a hydraulic cylinder for sensor input and brush positioning.
An electrical rotation sensor, such as a potentiometer or alternatively, a linear sensor as mentioned above, is coupled with the shaft that supports the springs or feelers. The sensor detects movement of the springs (also referred to as “feelers,” “spring feelers,” “feeler springs”) carried on the shaft that causes a signal to be sent to a controller. The controller in turn causes a proportional valve to reposition the shaker brush, moving the shaker brush inwardly or more outwardly as needed. The repositioning of the shaker brush drives a potentiometer error signal toward zero, which thus establishes a new equilibrium point between the potentiometer sensing feeler spring supporting shaft position and shaker brush position. This allows for adjustment of the shaker depending on the shape of the tree.
A “time-out” feature is used to shut off hydraulic pressure to the actuator that moves the shaker brush in and out when a constant retract error occurs for more than a set time, e.g. ten seconds. A constant retract (of the shaker brush) condition will occur when the harvester is at the end of a tree row, if there are large distances between trees, or if the harvester is stationary between trees, for instance. When the harvester is at an end of a row the new course taken by the harvester will be void of trees and therefore no sensing is needed. Thus, the spring feelers will, through the sensor carried on the shaft, indicate a “too wide” spacing error between opposed sets of shaker brushes and attempt to retract the shaker head until the error disappears.
After the harvester completes its turn or otherwise starts down the orchard row the error signal will disappear as the spring feeler host shaft will rotate in response to the feeler springs contacting the tree.
The attendant potentiometer will provide an output to the controller. The on board tree sensing and shaker brush adjusting control system will process the output and cause an associated brush actuator, a hydraulic ram, to reposition the shaker brush relative to the sensed tree. The control signal will thus have changed from “retract” to “extend” and the shaker brush will be repositioned accordingly.
For normal travel within the operational parameters of the placement in the orchard, a limit switch or alternatively, a mechanical stop, may be implemented to interrupt a retract signal. The retract signal, overridden by the limit switch, will position the shaker head at a preset position to prevent the shaker head from fully retracting.
Moreover, when the harvester is in a transport mode, where no trees, bushes or plants are to be engaged, the operator can override the limit switch or alternatively override the mechanical stop. Thus, the shaker brushes will remain fully retracted. This results in minimization of the width dimension of the harvester allowing for travel that is more efficient.
The shaker brush position, which is normally controlled during the harvesting operation by the electronic control system, i.e. the controller, operating various hydraulic valve circuits of the harvester, can also be controllable by the harvester operator. He can manually switch the shaker brush control from an “auto” mode to a “jog” mode. In the jog mode, the operator of the harvester can use a jog switch to move and hold each individual shaker brush at a desired position within a range of parameters.
This invention also concerns an automatic steering correction system for a harvester. It is usual to have a harvester equipped with a pair of rail sensors affiliated with a pair of front guide rails. A second pair of rail sensors, located at the rear of the harvester vehicle, is used in this invention to indicate the position of the back end of the harvester. The harvester operator is alerted when the rear wheels are being steered automatically by the control system with indicator lights in the cab of the vehicle. Such automatic steering will happen when the rear guide rail sensors send a signal to the controller that the harvester is not tracking the tree row evenly. Alternatively, the vehicle itself can be programmed to react to an unusual steering situation by an input to a manual input device, for instance, a keyboard input device, that can be used to program the automatic control system. In essence, there is a semi-automatic operation where the operator receives sensory input from the system or fully automatic steering where steering corrections are made automatically without operator control.
II. Description of Related Information
In one style of harvesting, it is known to remove fruit, such as grapes, nuts, citrus fruit and olives, from vines or trees using a shaker brush powered by a force balanced shaker. Present machines travel down one side of a row of trees and harvest olives from that side of the trees. A more complex type of harvester, an “over-the-row” machine, straddles the tree or vines. The profile of the tree is generally conical in shape with appropriate spacing between the trees to allow for the harvesters, tree trimmers, and workers, to complete the work necessary to harvest the crop and maintain optimum health of the trees.
To pick the olives effectively, it is necessary to move the shaker head, in a single head unit that harvests from one side of the tree at a time, or in an over-the-row harvester where two opposed shaker heads are used, toward and away from a tree row centerline to properly engage shaker rods or tines (which make up tree contacting elements of the “shaker brushes”) with the tree as the harvester travels along the row. The trees have what may be termed a front side, that portion of the tree on the side being approached by the harvester shaker and a back side of the tree on the side of the tree away from the approaching harvester. Good shaker contact with the side of the tree is easy. Good shaking contact with the front and the backside of the tree is more difficult. To accomplish harvesting with the shakers known in the art, more typically, harvesters that have only one shaker brush and harvest from the side, the shaker positioning is manually controlled. Starting between trees, the shaker is moved inward at the front side of the tree toward the tree row centerline. As the leading side of the shaker engages the tree it must be rapidly pulled outward away from the tree centerline as the harvester machine travels forward to move around the side of the tree. Then, the trailing side of the shaker must be moved rapidly from engagement with the side of the tree inwardly towards the tree centerline to engage the backside of the tree. The high forces imparted by the shaker engaging the tree results in olives flying off the tree in all directions as the tree is shaken. As a result, the person controlling the position of the shaker must look through a protective screen in order to avoid being struck by olives. The screen results in diminished visibility of the person controlling the position of the shakers while observing the tree, the olives, and the moving shakers. In short, it is physically and mentally taxing on the operator to reposition the shaker head for optimum fruit removal and minimum tree damage.
Various patents pertaining to harvesters are know to the inventors. U.S. Pat. No. 5,904,034 discloses a machine that has a hydraulic cylinder to bias a picking head to contact the trees. One deficiency in this design is that if the harvester is not on level ground the brush will be urged by gravity either in toward the tree thereby generating too much force on the tree or, depending on the slope of the ground, away from the tree and thereby not getting the contact with the tree that yields optimum harvesting. The biasing cylinder must be set to a low enough pressure to avoid excessive penetration of the tree by the rods. In this patent there are no sensors for sensing the tree and then automatically adjusting the position of the shaker head relative to the tree.
It is also known to use rods on a shaker head to harvest fruit. In U.S. Pat. No. 4,860,529 no sensors are used to sense the position of the tree relative to the shaker head.
It is also known to use a shaker head including a force-balanced shaker with the shaker head movable to approach at least three sides of a tree. No sensor springs are disclosed in U.S. Pat. No. 5,661,963, and there is no feed back system for automatically adjusting the depth of shaker rod penetration into the tree.
It is also known to provide a harvester that has multiple shaker heads on a single chassis. In U.S. Pat. No. 5,423,166, there is no provision for automatic positioning of a shaker head responsive to feeler springs associated with the shaker heads.
It is also known to provide an over-the-top harvester as shown in U.S. Pat. No. 5,067,314. No sensor responsive device depending on feeler springs is taught by this patent.
Each of the above mentioned patents are hereby incorporated by reference. None of these above mentioned patents disclose a system and method for harvesting using shaker brushes that are sensor responsive using feeler springs as is disclosed herein.
A problem relating to the manual positioning of shakers is the number of workers required in moving the shakers in and out of position during operation of such a harvester. Increased operating cost is reflected in such harvesting systems because as more workers are needed to operate the machinery higher operating costs accrue.
Also a problem is the decreased fruit removal rates observed in a manual operation of a force balanced shaker harvester.
In one embodiment of this invention, an automatic steering system is incorporated in the harvester. In prior art harvesters an automatic steering system using a guide wire, grapevine trunk, curb edge, or visual feedback are used. For example, one way to steer a harvester is to use side rails that sense relative tree trunk side-to-side position and automatically direct hydraulic oil to a steering cylinder to drive an error signal towards zero to steer front wheels of the harvester.
Problems relating to steering a harvester apparatus caused by the relatively long wheelbase of the harvester need to be overcome. A wheelbase of approximately two hundred fifty inches in combination with a requirement to turn the harvester within a thirty-foot radius, the maneuvering space at the beginning and end of each tree row, creates maneuverability issues for the harvester. To accomplish efficient turning movements in this invention, both front and rear wheels are steerable wheels. For example, for a left turn, the front wheels turn left while the rear wheels turn a corresponding amount to the right. This causes the harvester to turn about a centerline located along a line perpendicular to the travel and approximately halfway between the front and rear wheels. An operator positioned at the operator's station at the front of the harvester cannot judge the harvesters trailing position. Thus, if the operator sharply turns at the end or beginning of a row, the harvester rear will swing out and not line up with the tree row centered under the straddling harvester. Therefore, damage to the tree and/or machine will likely occur. If the operator selects to steer with only the front wheels, the rear wheels will “cut over,” that is not track with the front wheels, with the same result (but usually on a smaller diameter of the turn) as above.
Another problem addressed by this invention concern access to the force balanced drive device. A new mounting technique is included in this invention wherein a collar supports the shaker brush below the force-balanced drive. This means that access to the drive is possible without having to remove the shaker brush or its substantial mounting hardware. Previously, that is in earlier designs, the support for the shaker brush was above the drive unit. This blocked access to the force balanced shaker unless the shaker brush support was first removed.